During completions and production stages of a well, various tools are installed in the well. For example, electric submersible pumps (ESPs) are an artificial-lift method used which involve a sealed motor and pump placed deep in a well and hung on production tubing. During the installation of the ESP system, thousands of feet of tubing, hydraulic control lines, power cables, and electric control lines are installed in the well through a BOP stack. These lines and cables are typically bundled and clamped together onto the surface of the production tubing.
If a well control event were to occur while these lines and cables are on the production tubing traversing the BOP stack, a blind shear ram (BSR) is typically the only preventer available to seal the well. However, when the BSR is actuated, the production tubing, including the bundle of control lines and cables, are sheared and drop into the well, causing further damage and loss.
One way of sealing a well without shearing the production tubing is the use of ram packers and annular BOPs. Ram packers and annular BOPs are a preferable well control device because they do not cause damage to the bundle and do not sever or drop the ESP assembly into the well. Rather, ram packers and annular BOPs constrict around the production tubing when actuated. However, they are ineffective when used with production tubing having an irregular outer profile, such as when lines and cables are disposed on the production tubing, because the packers cannot fill the crevices and gaps in the irregular profile.